A shrinking share of California’s 17.7 million voters have a party affiliation, a situation that has helped foster a niche industry of campaign literature tailored to voters without a party preference.

Candidates and statewide ballot measure campaigns have taken notice. State filings show that, during the last election cycle, dozens of campaign committees paid a total of almost $200,000 to a pair of slate mailers with titles aimed at appealing to the almost one-quarter of California voters without a party preference: the Independent Voters League and the No Party Preference Voter Guide.

That amount is about three times what campaigns paid to similarly named slates during the 2011-2012 election cycle, records show.

Paul Fickas, a consultant who produces the NPP guide, has begun signing up candidates and ballot measures for his 2016 edition. Fickas, who estimated he sent out more than 500,000 slate mailers in all of 2014, expects to mail 450,000 pieces leading up to next November’s election.

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“I think they appreciate getting something, that they’re being recognized,” Fickas said of the state’s 4.2 million no-party preference voters. “There’s a hunger out there right now because they don’t think they’re being represented.”

No-party preference voters tend to be younger than registered Democrats or Republicans. San Francisco, San Jose, Irvine and San Diego have the largest shares of no-party voters among the state’s large cities.

There’s no guarantee, though, that slates aimed at NPP voters will include actual NPP candidates. Candidates of both parties paid for spots on Fickas’ slate last year. Even in the contest for secretary of state, which featured well-funded independent contender Dan Schnur, a former chairman of the Fair Political Practices Commission, the NPP slate featured Democrat Alex Padilla. Padilla was the first to reserve a spot, Fickas said.

State regulations require slates to note that campaigns have paid for a spot on the mailer. And it’s unusual for space on a slate to go wanting.

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